docs: improve website accessibility and seo

Author: lwouis

docs/_layouts/default.html

@@ -5,6 +5,7 @@
     <meta http-equiv="content-type" content="text/html; charset=utf-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta name="description" content="Windows alt-tab on macOS">
 
     <title>
         {% if page.title == "Introduction" %} {{ site.title }} - {{ site.description }}
@@ -37,7 +38,7 @@
 
 <header>
     <div>
-        <a href="{{ site.baseurl }}"><img src="{{ site.baseurl }}public/android-chrome-256x256.png" width="100" height="100"/></a>
+        <a href="{{ site.baseurl }}" aria-label="Homepage"><img src="{{ site.baseurl }}public/android-chrome-256x256.png" width="100" height="100" alt="AltTab logo"/></a>
         <div>
             <h1><a href="{{ site.baseurl }}">{{ site.title }}</a></h1>
             <p>{{ site.github.project_tagline }}</p>